MDM4 and angiosarcoma: Due to the rarity of cardiac angiosarcomas, only a few gene mutations have been reported so far, these include KDR (G618R), MDM4,[10] POT1 gene missense mutation in TP53-negative Li-Fraumeni-like family,[11] numerical and structural changes in the chromosomes and the p53 gene.[12] KDR, also called VEGFR-2, plays an important role in angiogenesis and vasculogenesis.